## NetCDF synoptic data for multiple profiles

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##### Revision as of 13:34, 21 October 2016 by imported>Lang Guenther (→Version Discrete Sampling Geometry trajectoryProfile: text on example variable added to page)

# Short Description

Synoptic data for several profiles with different number of locations along each profile.

# Further Descriptions

- NetCDF multiple profiles: coordinates and coordinate transformation for multiple profiles.
- NetCDF time coordinate: coordinate variable
*time*. - NetCDF vertical coordinate: time and location dependent vertical coordinate.

# Version *Discrete Sampling Geometry* **trajectoryProfile**

Data for multiple locations along one or several profiles (trajectories) are stored in a netCDF file in accordance with the concept of a *Discrete Sampling Geometry* with **featureType=trajectoryProfile**. An example (output from NCDUMP) for geometry as well as data is shown in

.

This type of data is essentially identical with netCDF synoptic data at multiple locations. All relevant differences, which are the same for all geophysical variables, are explained for variable water level.

float Mesh0_node_Wasserstand_2d(nMesh0_data_time, nMesh0_trajectory, nMaxMesh0_trajectory_nodes) ;

- :long_name = "Wasserstand [ node ]" ;
- :units = "m" ;
- :name_id = 3 ;
- :_FillValue = 1.e+31f ;
- :ancillary_variables = "Mesh0_node_Gesamtwassertiefe_2d" ;
- :cell_measures = "area: Mesh0_node_Wasserflaeche_2d" ;
- :cell_methods = "nMesh0_data_time: point area: mean" ;
- :comment = "ancillary variables may be used for visualization and data analysis as threshold and plot subgrid mask" ;
- :coordinates = "Mesh0_node_lon Mesh0_node_lat Mesh0_node_x Mesh0_node_y Mesh0_trajectory_long_name Mesh0_trajectory_node_distance" ;
- :grid_mapping = "Mesh0_crs" ;
- :standard_name = "sea_surface_height" ;

The following essential differences with respect to data defined for multiple locations exist:

- There are two instead of one (horizontal) dimensions:
*nMesh0_trajectory*corresponds to the number of trajectories and*nMaxMesh0_trajectory_nodes*reflects the (maximum) number of locations for a trajectory. Using the two independent dimensions allows easy access to data along a single trajectory. - Auxiliary coordinate variable
**Mesh0_trajectory_node_distance**is available. With this coordinate variable it is easy to display data along a trajectory in dependence on coordinate profile-meter.

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